The easiest way to draw a rotation is to use tracing paper, this should be available to you in an exam but you may have to ask an invigilator for it
Place the tracing paper over page and draw over the original object
Place the point of your pencil on the centre of rotation
Rotate the tracing paper the angle that has been asked for in the question, it will usually be an "easy" angle such as 90 ^{o}, 180 ^{o} or 270 ^{o}
Using tracing paper, draw over the original object and mark one vertex.
Mark on the centre of rotation.
Draw an arrow pointing vertically upwards on the paper.
With your pencil fixed on the point of rotation, rotate the tracing paper 90 ^{o} anti-clockwise, the arrow that you drew should now be pointing left.
Make a mental note of the new coordinates of the vertex that you marked on your tracing paper.
Draw the new position of this vertex onto the grid.
Repeat this process for the other two vertices on the triangle.
Connect the vertices together to draw the rotated image.
You should be able to see that the object has been rotated 90 ^{o} clockwise (or 270 ^{o} anti-clockwise).
You are likely to be able to see roughly where the centre of rotation is but it may take a little time to find its position exactly.
To find the exact coordinates of the centre of rotation you can play around with tracing paper.
Draw over shape A on tracing paper, then try out different locations for the centre of rotation by placing your pencil on a point, rotating the paper 90 ^{o} clockwise and seeing if it lines up with shape B.
Write down the all of the elements required to fully describe the transformation: the type of transformation, the centre of rotation, the angle and the direction.
Rotation, 90 ^{o} clockwise with centre (-4, 0)